1. Field of the Invention
The present invention relates to a solid-state imaging apparatus.
2. Description of the Related Art
As a solid-state imaging apparatus used for an electronic camera or the like, Japanese Patent Application Laid-Open No. 2000-232216 has been disclosed. The solid-state imaging apparatus has two or more sets of photodiodes (PDs) and transfer MOS transistors, performs reading out to a common floating diffusion (FD) region, and performs amplification by a common source follower MOS transistor.
Moreover, Japanese Patent Application Laid-Open No. 2000-165755 has disclosed a unit for providing a solid-state imaging apparatus in which a MOS capacitor is added to an FD so that an FD capacitor is variable, and sensitivity can be changed corresponding to signal electric charges accumulated in a photoelectric conversion section. It is possible to reduce an output signal amplitude when a large amount of electric charges are transferred to the FD, and to suppress an amplitude of a voltage on and after a vertical signal line, by increasing the FD capacitor.
However, Japanese Patent Application Laid-Open No. 2000-232216 increases the FD capacitor itself by having a common FD, and thus has a problem of a degraded SN ratio (Signal to Noise ratio).
Moreover, Japanese Patent Application Laid-Open No. 2000-165755 requires a capacitor unit for causing the FD capacitor to be electrically variable, and thus has a problem of an increased number of elements within a pixel and a reduced PD area.
An object of the present invention is to provide a solid-state imaging apparatus which can cause an FD capacitor value to be variable without increasing the number of elements.